Japanese Math and Logic Puzzle
Puzzle 16 of Celtic Mythology Hard Pack
Question is: Japanese Math and Logic Puzzle
and the answer is: KAKURO
Word Meaning:
KAKURO — (games) A type of number puzzle, similar to a crossword but with numbers. Each "clue" is the sum of the digits to be placed in its group of squares, and no digit can be repeated within a group.
Definitions from Wiktionary.